Gas distribution assembly and water-heating device including the same

ABSTRACT

The present disclosure provides a gas distribution assembly and a water-heating device including the same. The gas distribution assembly for distributing a gas to a plurality of burners includes a manifold unit detachably assembled to an outer surface of a combustion chamber in which the plurality of burners are received, the manifold unit including a plurality of gas nozzles that eject the gas to gas inlets of the burners through an opening of the combustion chamber, and a gas supply unit that is assembled to the manifold unit so as to be separable and that supplies, to the manifold unit, the gas introduced into the gas supply unit. The manifold unit is separated from the combustion chamber and the gas supply unit as needed for replacement.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to Korean Patent Application No. 10-2019-0113101, filed in the Korean Intellectual Property Office on Sep. 11, 2019, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a gas distribution assembly and a water-heating device including the same, and more particularly, relates to a gas distribution assembly for facilitating conversion of a gas appliance from one fuel type to another and a water-heating device including the gas distribution assembly.

BACKGROUND

A gas appliance that uses gas as a fuel mixes the gas with air at an appropriate ratio, supplies the mixture to a burner, burns the mixture in the burner through an ignition device, and supplies heat of combustion. For example, in a case where the gas appliance is a water-heating device such as a water heater, heat of combustion is supplied to a heat exchanger, and hot water is produced through heat exchange. A product has to be selected and used depending on the type of gas desired to be used, or in a case where gas to be in use is changed, gas nozzles for supplying the gas to a burner have to be replaced depending on gas desired to be used.

For example, because liquefied petroleum gas (hereinafter, referred to as LPG) differs from liquefied natural gas (hereinafter, referred to as LNG) in terms of characteristics such as a heating value, and the like, sizes of gas nozzles need to be changed so as to use LPG for a product that uses LNG. In addition, a control program may also be changed.

In the related art, because a member having gas nozzles is integrally formed with a member that receives gas and to which electric wires are connected, the number of replaced parts and processes for changing the type of gas is increased, which leads to an increase in cost and time. In addition, because re-assembly of the electric wires is needed, a possibility that the electric wires are incorrectly assembled may be increased.

SUMMARY

The present disclosure has been made to solve the above-mentioned problems occurring in the prior art while advantages achieved by the prior art are maintained intact.

An aspect of the present disclosure provides a gas distribution assembly for providing an effect of cost savings by reducing the number of replaced parts and processes by replacing only a manifold unit when a gas nozzle needs to be changed for conversion of a gas appliance from one fuel type to another, and a water-heating device including the gas distribution assembly.

Another aspect of the present disclosure provides a gas distribution assembly for minimizing a possibility of malfunction of a product according to separation and re-assembly of electric wires when a manifold unit is replaced for conversion of a gas appliance from one fuel type to another, and a water-heating device including the gas distribution assembly.

The technical problems to be solved by the present disclosure are not limited to the aforementioned problems, and any other technical problems not mentioned herein will be clearly understood from the following description by those skilled in the art to which the present disclosure pertains.

According to an aspect of the present disclosure, a gas distribution assembly for distributing a gas to a plurality of burners includes a manifold unit detachably assembled to an outer surface of a combustion chamber in which the plurality of burners are received, the manifold unit including a plurality of gas nozzles that eject the gas to gas inlets of the burners through an opening of the combustion chamber, and a gas supply unit that is assembled to the manifold unit so as to be separable and that supplies, to the manifold unit, the gas introduced into the gas supply unit. The manifold unit is separated from the combustion chamber and the gas supply unit as needed for replacement.

The manifold unit may be separated from the combustion chamber and the gas supply unit and may be replaced with another manifold unit, when the gas nozzles need to be changed due to a change in the type of the gas supplied into the burners.

The manifold unit may include a manifold having the gas nozzles on a surface of the manifold that is detachably coupled to the combustion chamber and that faces in a first direction, a direction from the manifold unit to the combustion chamber being referred to as the first direction and a direction opposite to the first direction being referred to as a second direction, and a front panel that is detachably assembled to a surface of the manifold facing in the second direction and that covers the manifold.

The manifold may include a manifold body having a space sealed by the front panel, partition walls that partition the space of the manifold body into a plurality of regions, and a plurality of inflow holes formed in the manifold body so as to be disposed in the plurality of regions. The gas nozzles may connect to the inflow holes, and the gas supply unit may include a plurality of supply holes located to correspond to the plurality of inflow holes so as to supply the gas to the plurality of regions.

Sizes of the plurality of inflow holes may be determined based on sizes of the regions, and gas travel paths along which in the regions, the gas moves from the inflow holes toward the gas nozzles.

One of the plurality of regions may be referred to as a first region, and another one of the plurality of regions may be referred to as a second region. The inflow hole located in the first region may have a larger size than the inflow hole located in the second region, when the first region has a larger size than the second region.

One of the plurality of regions may be referred to as a first region, and another one of the plurality of regions may be referred to as a second region. The inflow hole located in the second region may have a larger size than the inflow hole located in the first region, when a distance from the gas nozzle located in the first region to the supply hole connecting to the first region is shorter than a distance from the gas nozzle located in the second region to the supply hole connecting to the second region.

The manifold may include a first fastening hole for assembly of the manifold and the combustion chamber, a second fastening hole for assembly of the manifold and the gas supply unit, and a third fastening hole for assembly of the manifold and the front panel.

The manifold unit may further include a first packing member that forms a seal between the manifold and the front panel and a second packing member that forms a seal between the manifold and the gas supply unit assembled to the surface of the manifold that faces in the first direction.

The gas supply unit may include a supply part including a main body that has the plurality of supply holes formed therein and a gas supply pipe that is integrally formed with the main body and into which the gas is supplied and a valve part including a plurality of solenoid valves that open and close the plurality of supply holes.

The main body may include a dispersion space that is connected with an outlet of the gas supply pipe and that is open in the second direction and a plurality of insertion spaces into which the plurality of solenoid valves are inserted and that are open in the first direction. The supply holes may be formed in surfaces of the insertion spaces that face in the second direction. The main body may include side-surface connecting holes that are formed through side surfaces perpendicular to the surfaces of the insertion spaces facing in the second direction and that connect the insertion spaces and the dispersion space. The side-surface connecting holes provided for the insertion spaces located adjacent to each other among the plurality of insertion spaces may be formed to face each other.

According to another aspect of the present disclosure, a water-heating device includes a case that has a storage space formed therein and that includes a case cover that opens and closes one side of the case, a combustion chamber that is received in the storage space and that has an interior space in which a combustion reaction occurs, a plurality of burners received in the interior space of the combustion chamber, and a gas distribution assembly that is provided between the case and the combustion chamber and that distributes a gas to the plurality of burners. A direction from the gas distribution assembly to the combustion chamber is referred to as a first direction, and a direction from the gas distribution assembly to the case cover is referred to as a second direction, the second direction being opposite to the first direction. The gas distribution assembly includes a manifold unit including a plurality of gas nozzles that eject the gas to gas inlets of the burners through an opening of the combustion chamber, a surface of the manifold unit facing in the first direction being detachably assembled to an outer surface of the combustion chamber, and a gas supply unit that is connected to a supply valve unit and is assembled to the manifold unit so as to be separable and that supplies, to the manifold unit, the gas introduced from the supply valve unit. The manifold unit is separated from the combustion chamber and the gas supply unit as needed for replacement.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings:

FIG. 1 is a perspective view illustrating a water-heating device according to an embodiment of the present disclosure;

FIG. 2 is an exploded perspective view illustrating a combustion chamber and a gas distribution assembly according to the present disclosure;

FIG. 3 is a perspective view illustrating the gas distribution assembly according to the present disclosure;

FIG. 4 is a side view illustrating the gas distribution assembly of FIG. 3;

FIG. 5 is an exploded perspective view illustrating the gas distribution assembly of FIG. 3;

FIG. 6 is a perspective view of a manifold illustrated in FIG. 5;

FIG. 7 is a perspective view of a gas supply unit illustrated in FIG. 5; and

FIG. 8 is a front view of the gas supply unit illustrated in FIG. 7.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

The following embodiments are embodiments appropriate for the understanding of technical features of a gas distribution assembly and a water-heating device including the same according to the present disclosure. However, the present disclosure is not limited to the following embodiments, and technical features of the present disclosure are not restricted by the following embodiments. Furthermore, various changes and modifications can be made without departing from the spirit and scope of the present disclosure.

Referring to FIGS. 1 and 2, a water-heating device 10 according to the present disclosure includes a case 11, a combustion chamber 20, a plurality of burners 30, and a gas distribution assembly 100.

The case 11 includes a case cover 13 that opens and closes one side of the case 11. The case 11 has a storage space formed therein. The case 11 may further include a case housing 12 that forms the storage space. The case cover 13 may be assembled to the case housing 12 so as to be separable.

The combustion chamber 20 is received in the storage space and has an interior space in which a combustion reaction occurs. The combustion chamber 20 may include a combustion chamber housing 21 that forms the interior space and a combustion chamber cover 25 assembled to the combustion chamber housing 21 so as to be separable. An opening 26 may be formed through the combustion chamber cover 25.

The plurality of burners 30 are received in the interior space of the combustion chamber 20. The plurality of burners 30 may be disposed in a row on a burner body 31 mounted in the combustion chamber 20. The plurality of burners 30 include a gas inlet through which a gas is introduced.

The water-heating device 10 may include a heat exchanger 40 in which heat exchange is performed by heat of combustion from the burners 30 and an exhaust gas guide plate 53 having an exhaust hole formed therein for releasing combustion gases originating from the inside of the combustion chamber 20. Furthermore, the water-heating device 10 may include an intake gas guide plate 51 having an air supply hole formed therein for introducing air into the case 11, and an air supply duct 60 and a blower 70 for supplying the introduced air into the combustion chamber 20. In addition, the water-heating device 10 may include an ignition transformer 91 and an electrode rod 93 for ignition in the combustion chamber 20. Reference numeral 94 denotes a panel member coupled to the case cover 13, and reference numeral 95 denotes a control member for controlling operation of the water-heating device 10.

The gas distribution assembly 100 distributes the gas to the plurality of burners 30 and is located between the case cover 13 and the combustion chamber 20.

Hereinafter, the gas distribution assembly 100 will be described in detail. For convenience of description, a direction from the gas distribution assembly 100 to the combustion chamber 20 is referred to as a first direction D1, and a direction from the gas distribution assembly 100 to the case cover 13 is referred to as a second direction D2. The second direction D2 is opposite to the first direction D1.

The gas distribution assembly 100 includes a manifold unit 200 and a gas supply unit 300.

A surface of the manifold unit 200 that faces in the first direction D1 is detachably assembled to an outer surface of the combustion chamber 20. The manifold unit 200 includes a plurality of gas nozzles 212 that eject the gas to the gas inlets of the burners 30 through the opening 26 of the combustion chamber 20.

The gas supply unit 300 is assembled to the manifold unit 200 so as to be separable and supplies the introduced gas to the manifold unit 200. The water-heating device 10 may further include a supply valve unit 80 connected with a gas supply source, and the gas supply unit 300 may be connected to the supply valve unit 80. The gas supply unit 300 may supply, to the manifold unit 200, the gas introduced from the supply valve unit 80.

The manifold unit 200 according to the present disclosure may be separated from the combustion chamber 20 and the gas supply unit 300 as needed for replacement. Specifically, the gas distribution assembly 100 according to the present disclosure may be separated into the manifold unit 200 and the gas supply unit 300. In a case where the manifold unit 200 needs to be replaced, only the manifold unit 200 may be replaced by separating the case cover 13 in a state in which operation of the water-heating device 10 is stopped, maintaining the manifold unit 200 in a state of being coupled with parts and the gas supply unit 300 in the case 11, and separating the manifold unit 200 from the combustion chamber 20 and the gas supply unit 300.

For example, in a case where the type of the gas supplied into the burners 30 is changed and therefore the gas nozzles 212 need to be changed, the manifold unit 200 having the gas nozzles 212 needs to be replaced. In this case, only the manifold unit 200 may be separated and replaced with another manifold unit 200 including gas nozzles 212 appropriate for the changed gas because the manifold unit 200 is provided to be separable from the gas supply unit 300.

For example, in a case where the water-heating device 10 using LNG gas is produced and thereafter a used gas has to be changed from LNG gas to LPG gas depending on an installation environment, the manifold unit 200 may be replaced with another manifold unit 200 including gas nozzles 212 appropriate for LPG gas. Here, the manifold unit 200 may serve as a conversion kit when conversion, such as changing the type of gas, is required.

When the gas distribution assembly 100 according to the present disclosure is used, only the manifold unit 200 may be replaced in a case where the gas nozzles 212 need to be changed for conversion of the water-heating device 10 from one fuel type to another. Thus, an effect of cost savings may be obtained due to a reduction in the number of replaced parts and processes for the conversion. In addition, the present disclosure may minimize a possibility of malfunction of the product according to separation and re-assembly of electric wires because it is not necessary to separate the gas supply unit 300 to which the supply valve unit 80 and all the electric wires are assembled to supply the gas to the manifold unit 200.

Referring to FIGS. 3 and 5, the manifold unit 200 according to the present disclosure may include a manifold 210 and a front panel 250.

As described above, the direction from the manifold unit 300 to the combustion chamber 20 may be referred to as the first direction D1, and the opposite direction to the first direction D1 may be referred to as the second direction D2. The gas nozzles 212 may be formed on a surface of the manifold 210 that faces in the first direction D1 and that is detachably coupled to the combustion chamber 20.

The front panel 250 may be detachably assembled to a surface of the manifold 210 that faces in the second direction D2 and may cover the surface of the manifold 210 that faces in the second direction D2.

More specifically, the manifold 210 may include a manifold body 211 having a space sealed by the front panel 250, partition walls 213 that partition the space of the manifold body 211 into a plurality of regions 216, and a plurality of inflow holes 215 formed in the manifold body 211 so as to be located in the plurality of regions 216. Here, the gas nozzles 212 may connect to the inflow holes 215. The gas introduced through the inflow holes 215 may move to the gas nozzles 212 and may be ejected to the gas inlets (not illustrated) of the burners 30 that are located in the first direction D1.

The gas supply unit 300 may include a plurality of supply holes 323. The plurality of supply holes 323 a, 323 b, 323 c, and 323 d may be located to correspond to the plurality of inflow holes 215 a, 215 b, 215 c, and 215 d so as to supply the gas to the plurality of regions 216 a, 216 b, 216 c, and 216 d.

For example, in the embodiment illustrated in FIG. 6, a space may be formed on a surface of the manifold body 211 that faces in the second direction D2 and may be open in the second direction D2. The space may be divided into the four regions 216 a, 216 b, 216 c, and 216 d by the partition walls 213. The same or different number of gas nozzles 212 may be formed in the regions 216 a, 216 b, 216 c, and 216 d, and the four inflow holes 215 a, 215 b, 215 c, and 215 d may be formed to correspond to the regions 216 a, 216 b, 216 c, and 216 d. The four supply holes 323 a, 323 b, 323 c, and 323 d may be formed in the gas supply unit 300 to correspond to the regions 216 a, 216 b, 216 c, and 216 d. The supply holes 323 a, 323 b, 323 c, and 323 d may be located to correspond to the inflow holes 215 a, 215 b, 215 c, and 215 d when the gas supply unit 300 is assembled to the manifold unit 200. However, the number of regions 216 separated from one another by the partition walls 213 is not limited to the illustrated embodiment.

Here, the sizes of the inflow holes 215 a, 215 b, 215 c, and 215 d may be determined in consideration of the sizes of the regions 216 a, 216 b, 216 c, and 216 d and gas travel paths along which in the regions, the gas moves from the inflow holes 215 a, 215 b, 215 c, and 215 d to the gas nozzles 212.

More specifically, one of the plurality of regions 216 may be referred to as a first region, and another one of the plurality of regions 216 may be referred to as a second region. When the size of the first region is greater than the size of the second region, the size of the inflow hole 215 located in the first region may be greater than the size of the inflow hole 215 located in the second region.

Alternatively, one of the plurality of regions 216 may be referred to as a first region, and another one of the plurality of regions 216 may be referred to as a second region. When the gas nozzle 212 located in the first region is closer to the supply holes 323 than the gas nozzle 212 located in the second region, the size of the inflow hole 215 located in the first region may be greater than the size of the inflow hole 215 located in the second region.

That is, as in the illustrated embodiment, depending on an environment in the case 11, the gas supply unit 300 or the supply holes 323 may be eccentrically assembled to one side of the manifold body 211 rather than the center thereof. In this case, the paths along which the gas moves in the regions 216 a, 216 b, 216 c, and 216 d may differ from each other. Accordingly, the sizes and positions of the inflow holes 215 according to the present disclosure may be determined in consideration of the gas travel paths along which the gas moves.

For example, as in the embodiment illustrated in FIGS. 5 and 6, the space may be partitioned into four spaces (that is, region A 216 a, region B 216, region C 216 c, and region D 216 d) by three partition walls 213. In this case, the inflow holes 215 a, 215 b, 215 c, and 215 d may be formed in the plurality of regions 216 a, 216 b, 216 c, and 216 d, respectively.

For example, when region A 216 a is referred to as a first region and region B 216 b is referred to as a second region, the degrees to which the first area and the second area are close to the supply holes 323 are similar to each other, but the sizes of the regions differ from each other. In this case, the size of the inflow hole 215 a in region A 216, which is the first area having a relatively large size, may be greater than the size of the inflow flow 215 in the second region.

For example, when region A 216 a is referred to as a first region and region D 216 d is referred to as a second region, the sizes of the regions are similar to each other, but the gas nozzle 212 in region A 216 a is closer to the supply holes 323 than the gas nozzle 212 in region D 216 d. The gas supply unit 300 is eccentrically assembled to one side of the manifold unit 200, and region A 216 a is disposed closer to the gas supply unit 300 than region D 216 d. In this case, the size of the inflow hole 215 d in region D 216 b, which is the second region, may be greater than the size of the inflow hole 215 a in region A 216 a.

However, the space of the manifold body 211 according to the present disclosure is not limited to being partitioned into the four regions 216 as in the illustrated embodiment, and various modifications can be made.

The manifold 210 may include first fastening holes 217 for assembly of the manifold 210 and the combustion chamber 20, second fastening holes 218 for assembly of the manifold 210 and the gas supply unit 300, and third fastening holes 219 for assembly of the manifold 210 and the front panel 250. Fastening screws may be threaded into the first fastening holes 217, the second fastening holes 218, and the third fastening holes 219 such that the manifold 210 is assembled so as to be separable.

The manifold unit 200 may further include a first packing member 261, a second packing member 262, and a third packing member 263.

The first packing member 261 may form a seal between the manifold body 211 and the front panel 250. The second packing member 262 may form a seal between the manifold body 211 and the gas supply unit 300 assembled to a surface of the manifold body 211 that faces in the first direction D1. The third packing member 263 may form a seal between the manifold body 211 and the combustion chamber cover 25. The first to third packing members 261, 262, and 263 may be formed in a plate shape made of cork. Without being limited thereto, however, various modifications can be made.

Referring to FIGS. 7 and 8, the gas supply unit 300 according to the present disclosure may include a supply part 310 and a valve part 350.

The supply part 310 may include a main body 320 having the plurality of supply holes 323 formed therein and a gas supply pipe 330 that is integrally formed with the main body 320 and into which the gas is supplied. The gas supply pipe 330 may be directly or indirectly connected to the supply valve unit 80. The gas supply pipe 330 may include an inlet 331 into which the gas supplied through the supply valve unit 80 is introduced and an outlet 332 through which the introduced gas is supplied into the main body 320.

The valve part 350 may include a plurality of solenoid valves 351 that open and close the plurality of supply holes 323, respectively. More specifically, as many solenoid valves 351 as the supply holes 323 may be provided to open and close the plurality of supply holes 323, and the solenoid valves 351 may be coupled to the main body 320. Reference numeral 353 denotes sealing members (O-rings) between the solenoid valves 351 and the main body 320.

More specifically, the main body 320 may include a dispersion space 321 and a plurality of insertion spaces 322. The dispersion space 321 may be a space formed on part of a surface of the main body 320 that faces in the second direction D2. The dispersion space 321 may be open in the second direction D2 and may be connected with the outlet 332 of the gas supply pipe 330. The plurality of insertion spaces 322 may be spaces that are open in the first direction D1 and into which the plurality of solenoid valves 351 are inserted.

The supply holes 323 may be formed in surfaces 322 a of the insertion spaces 322 that face in the second direction D2. The main body 320 may include side-surface connecting holes 324 formed through side surfaces 322 b perpendicular to the surfaces 322 a of the insertion spaces 322 that face in the second direction D2. The side-surface connecting holes 324 may connect the insertion spaces 322 and the dispersion space 321. Here, the side-surface connecting holes 324 provided for the insertion spaces 322 adjacent to each other among the plurality of insertion spaces 322 may face each other.

The valve part 350 may have opening/closing holes 352 formed to correspond to the plurality of side-surface connecting holes 324 a, 324 b, 324 c, and 324 d. The side-surface connecting holes 324 may be opened or closed by the solenoid valves 351 and the opening/closing holes 352. The gas supplied into the burners 30 may be controlled in multiple stages by individually controlling the plurality of solenoid valves 351.

For example, the plurality of insertion spaces 322 may be formed parallel to each other over the dispersion space 321 so as to be spaced apart from each other. Because the side-surface connecting holes 324 of the adjacent insertion spaces 322 are formed to face each other, the side-surface connecting holes 324 may each be formed in a direction toward one of the adjacent insertion spaces 322 rather than a direction toward the outlet 332 of the gas supply pipe 330. Accordingly, the gas introduced into the dispersion space 321 from the outlet 332 may be guided to move to the portions in which the side-surface connecting holes 324 are formed and may be distributed and supplied into the insertion spaces 322. Due to the positions of the side-surface connecting holes 324, the gas introduced into the dispersion space 321 may be uniformly distributed and supplied into the plurality of insertion spaces 322 without being concentrated on the insertion space 322 adjacent to the outlet 332.

Hereinafter, a process of replacing the manifold unit 200 according to the present disclosure in the case of conversion of the water-heating device 10 from one fuel type to another will be described with reference to FIGS. 1, 2, and 5. First, the case cover 13 is separated, and the front panel 250 is separated. Thereafter, the manifold 210 is separated from the combustion chamber cover 25 and the gas supply unit 300. At this time, the gas supply unit 300 remains coupled to the parts in the case 11, and the electric wires connected to the solenoid valves 351 of the gas supply unit 300 are maintained in the mounted state.

Next, a manifold 210 including gas nozzles 212 having a different size may be fastened to the combustion chamber cover 25 and the gas supply unit 300. At this time, the third packing member 263 may be applied between the combustion chamber cover 25 and the manifold body 211, the first packing member 261 may be applied between the manifold body 211 and the front panel 250, and the second packing member 262 may be applied between the manifold body 211 and the gas supply unit 300. Accordingly, a possibility of gas leakage may be minimized. Thereafter, the replacement of the manifold unit 200 may be completed by assembling the case cover 13.

As described above, when the gas distribution assembly according to the present disclosure is used, only the manifold unit may be replaced in a case where the gas nozzles need to be changed for conversion of the water-heating device from one fuel type to another. Thus, an effect of cost savings may be obtained due to a reduction in the number of replaced parts and processes for the conversion. In addition, it is not necessary to separate the gas supply unit to which the supply valve unit and all the electric wires are assembled to supply the gas to the manifold unit. Thus a possibility of malfunction of the product according to separation and re-assembly of the electric wires may be minimized.

Hereinabove, although the present disclosure has been described with reference to exemplary embodiments and the accompanying drawings, the present disclosure is not limited thereto, but may be variously modified and altered by those skilled in the art to which the present disclosure pertains without departing from the spirit and scope of the present disclosure claimed in the following claims. 

What is claimed is:
 1. A gas distribution assembly for distributing a gas to a plurality of burners, the gas distribution assembly comprising: a manifold unit configured to be detachably assembled to an outer surface of a combustion chamber in which the plurality of burners are received, the manifold unit including a plurality of gas nozzles configured to eject the gas to gas inlets of the burners through an opening of the combustion chamber; and a gas supply unit detachably assembled to the manifold unit and configured to supply, to the manifold unit, the gas introduced into the gas supply unit, wherein the manifold unit is configured to be separated from the combustion chamber and the gas supply unit as needed for replacement.
 2. The gas distribution assembly of claim 1, wherein the manifold unit is configured to be separated from the combustion chamber and the gas supply unit and is configured to be replaced with another manifold unit, when the gas nozzles need to be changed due to a change in the type of the gas supplied into the burners.
 3. The gas distribution assembly of claim 1, wherein the manifold unit includes: a manifold having the gas nozzles on a surface of the manifold that is detachably coupled to the combustion chamber and that faces in a first direction, wherein a direction from the manifold unit to the combustion chamber is referred to as the first direction, and a direction opposite to the first direction is referred to as a second direction; and a front panel detachably assembled to a surface of the manifold that faces in the second direction and configured to cover the manifold.
 4. The gas distribution assembly of claim 3, wherein the manifold includes: a manifold body having a space sealed by the front panel; partition walls configured to partition the space of the manifold body into a plurality of regions; and a plurality of inflow holes formed in the manifold body so as to be disposed in the plurality of regions, wherein the gas nozzles connect to the inflow holes, and wherein the gas supply unit includes a plurality of supply holes located to correspond to the plurality of inflow holes so as to supply the gas to the plurality of regions.
 5. The gas distribution assembly of claim 4, wherein sizes of the plurality of inflow holes are determined based on sizes of the regions, and gas travel paths along which in the regions, the gas moves from the inflow holes toward the gas nozzles.
 6. The gas distribution assembly of claim 4, wherein one of the plurality of regions is referred to as a first region, and another one of the plurality of regions is referred to as a second region, and wherein the inflow hole located in the first region has a larger size than the inflow hole located in the second region, when the first region has a larger size than the second region.
 7. The gas distribution assembly of claim 4, wherein one of the plurality of regions is referred to as a first region, and another one of the plurality of regions is referred to as a second region, and wherein the inflow hole located in the second region has a larger size than the inflow hole located in the first region, when a distance from the gas nozzle located in the first region to the supply hole connecting to the first region is shorter than a distance from the gas nozzle located in the second region to the supply hole connecting to the second region.
 8. The gas distribution assembly of claim 3, wherein the manifold includes: a first fastening hole for assembly of the manifold and the combustion chamber; a second fastening hole for assembly of the manifold and the gas supply unit; and a third fastening hole for assembly of the manifold and the front panel.
 9. The gas distribution assembly of claim 3, wherein the manifold unit further includes: a first packing member configured to form a seal between the manifold and the front panel; and a second packing member configured to form a seal between the manifold and the gas supply unit assembled to the surface of the manifold that faces in the first direction.
 10. The gas distribution assembly of claim 4, wherein the gas supply unit includes: a supply part including a main body having the plurality of supply holes formed therein and a gas supply pipe that is integrally formed with the main body and into which the gas is supplied; and a valve part including a plurality of solenoid valves configured to open and close the plurality of supply holes.
 11. The gas distribution assembly of claim 10, wherein the main body includes: a dispersion space connected with an outlet of the gas supply pipe, the dispersion space being open in the second direction; and a plurality of insertion spaces into which the plurality of solenoid valves are inserted, the insertion spaces being open in the first direction, wherein the supply holes are formed in a surface of the insertion spaces that face in the second direction, wherein the main body includes side-surface connecting holes formed through side surfaces perpendicular to the surface of the insertion spaces that face in the second direction, the side-surface connecting holes being configured to connect the insertion spaces and the dispersion space, and wherein the side-surface connecting holes provided for the insertion spaces located adjacent to each other among the plurality of insertion spaces are formed to face each other.
 12. A water-heating device comprising: a case having a storage space formed therein, the case including a case cover configured to open and close one side of the case; a combustion chamber received in the storage space, the combustion chamber having an interior space in which a combustion reaction occurs; a plurality of burners received in the interior space of the combustion chamber; and a gas distribution assembly provided between the case and the combustion chamber and configured to distribute a gas to the plurality of burners, wherein a direction from the gas distribution assembly to the combustion chamber is referred to as a first direction, and a direction from the gas distribution assembly to the case cover is referred to as a second direction, the second direction being opposite to the first direction, wherein the gas distribution assembly includes: a manifold unit including a plurality of gas nozzles configured to eject the gas to gas inlets of the burners through an opening of the combustion chamber, wherein a surface of the manifold unit that faces in the first direction is detachably assembled to an outer surface of the combustion chamber; and a gas supply unit connected to a supply valve unit and assembled to the manifold unit so as to be separable, the gas supply unit being configured to supply, to the manifold unit, the gas introduced from the supply valve unit, and wherein the manifold unit is configured to be separated from the combustion chamber and the gas supply unit as needed for replacement. 